Getting my ducks in a row

[hayes]

So an interesting update... I mentioned before that the dealer changed the ABS system to match my actual tire size (265-70-16) and I have not had an ABS warning on the dash since then. Well today we finally got snow on the ground, so I was able to test the ABS in front of the house. BIG SURPRISE! The ABS system actually worked just fine! I had to run some errands, and slid on a few spots, and even on the road it still worked as expected.

The 4WD took a second to kick in first thing. When I first hit the gas, the back end spun out like I was still in 2WD, so I stopped all the wheels, gave it a second, then took off again, and this time 4WD was engaged. After that, no problems at all with it, guess it just needed a second to warm up.

So it looks like at this point the speedo and odometer are the only things not working correctly. At least now I don't have to worry about driving on ice!

I am confused - why did you need to change the ABS system? ABS shouldn't need to be adjusted for tire size... I believe you, I just don't know what I am missing.

Your 4wd shouldn't need to warm up. That sounds like a disconnect that has some wear in it. Or - did you just pop it into 4hi and mash the gas without first driving forward and wiggling the steering wheel? I'm so glad to be rid of that problematic assembly.

What did you get rid of? I have read your build thread on here and on ExpoPortal and I don't see what you are talking about. I am about to re-read the Expo build again.

[Shdwdrgn]

On my year of truck the ABS system has a 3-wire tire speed sensor. This means that there are sensors on both front wheels, but the third wire goes to the output shaft of the transmission, and the computer calculates the tire speed based on what gear size it thinks I have. Since we haven't found a way to change gear size in the PCM, the only other option was changing the tire size. This put the calculations within what the computer considers an acceptable margin of error, so everything seems to be working normally again.

Because of the 3-wire system, a setting for tire size had to be included in the ABS code so it could properly calculate the apparent tire rotation speed for the back wheels when trying to compare against the actual tire rotation speed of the front wheels.

[TBYODA]

What did you get rid of? I have read your build thread on here and on ExpoPortal and I don't see what you are talking about. I am about to re-read the Expo build again.

JD did the awd mode to the 4wd disconnect . See the following http://www.offroadtb.com/articles/tech- ... isconnect/
Also see this hopeful mod.
viewtopic.php?f=32&t=4760

[hayes]

On my year of truck the ABS system has a 3-wire tire speed sensor. This means that there are sensors on both front wheels, but the third wire goes to the output shaft of the transmission, and the computer calculates the tire speed based on what gear size it thinks I have. Since we haven't found a way to change gear size in the PCM, the only other option was changing the tire size. This put the calculations within what the computer considers an acceptable margin of error, so everything seems to be working normally again.

Because of the 3-wire system, a setting for tire size had to be included in the ABS code so it could properly calculate the apparent tire rotation speed for the back wheels when trying to compare against the actual tire rotation speed of the front wheels.

That makes sense. Thanks for the info.

What did you get rid of? I have read your build thread on here and on ExpoPortal and I don't see what you are talking about. I am about to re-read the Expo build again.

JD did the awd mode to the 4wd disconnect . See the following http://www.offroadtb.com/articles/tech- ... isconnect/
Also see this hopeful mod.
viewtopic.php?f=32&t=4760

Thanks for the link, I will check it out.

[Regulator1175]

On my year of truck the ABS system has a 3-wire tire speed sensor. This means that there are sensors on both front wheels, but the third wire goes to the output shaft of the transmission, and the computer calculates the tire speed based on what gear size it thinks I have. Since we haven't found a way to change gear size in the PCM, the only other option was changing the tire size. This put the calculations within what the computer considers an acceptable margin of error, so everything seems to be working normally again.

Because of the 3-wire system, a setting for tire size had to be included in the ABS code so it could properly calculate the apparent tire rotation speed for the back wheels when trying to compare against the actual tire rotation speed of the front wheels.

I am still puzzled about this. I have moved to 4.10s, SS rear axle, and 35s and I have yet to have any lights. ABS works as it should as well. I have at least 500 miles on the truck since the upgrades with no issues at all.

Sent from my SCH-I545 using Tapatalk

[Shdwdrgn]

Didn't you say you were coming from 373 gears though? I started with 342s, and I couldn't drive 20 miles without the ABS system going nuts. I dunno, maybe its nothing more than a difference in systems between the two years of vehicle?

[mikekey]

From all I've seen it seems to be the year of the vehicle. All the folks with problems have 2004 in common.

[Shdwdrgn]

And here I thought I was being smart when I specifically went looking for an 04-05. Ah well, there's only so much I can anticipate...